The scientists from the Doñana Biological Station in Seville, Spain who conducted the research, observed the birds rubbing orange, red and yellow pigments called carotenoids from their preen gland (located at the base of their tail feathers) to feathers on their necks, chests and backs more frequently during mating season.

Once they started to breed, and their eggs began to hatch, the colors disappeared from their plumage, leading the authors of the study to conclude that the primary function of the birds' cosmetic coloration may be related to mate choice. We're going to file this one under "strange but true"—but it's still nice to know that we're not the only species in the animal kingdom that likes to doll ourselves up.